As fluorinated graphites there are known polymeric fluorinated graphites having the formula of (CF).sub.n [hereinafter referred to "(CF).sub.n "] and those having the formula (C.sub.2 F).sub.n [hereinafter referred to "(C.sub.2 F).sub.n "] which are produced by allowing fluorine gas to react with a graphite material in a vessel maintained at a temperature of 350.degree. C. to 600.degree. C. (U.S. Pat. No. 4,139,474 to Watanabe et al.). It is also known that electric cells using such fluorinated graphites as an active material of a positive electrode in combination with alkali metals such as lithium as a negative electrode exhibit a high discharge voltage, a characteristic flat discharge curve and an excellent shelf life. (U.S. Pat. Nos. 3,536,532, 3,700,502 and 4,247,608). Further, it is disclosed that fluorinated graphites having the formula of (C.sub.X F).sub.n wherein x is a numerical value of 3.6 to 4.0 can be produced by allowing a mixed gas of fluorine and hydrogen fluoride to react with a carbon material [Chem. Ber., vol. 80, page 413 (1947)]. In the production of these fluorinated graphites, however, extensive fluorine gas must be employed and also high temperatures are required. Since such high temperatures as above are near the dissociation temperature of the C--F bond, lot of effort must be made to obtain the products at high yields. Moreover, under such conditions corrosion of the reaction vessel is extensive, and thus it may be said that these processes are disadvantageous for a production of fluorinated graphites on an industrial scale.
The present inventors have therefore made extensive studies to develop an industrially advantageous process for producing fluorinated graphites avoiding the defects of the conventional techniques. As a result, the inventors have found that this purpose can be accomplished by electrolytically fluorinating a carbon material in hydrogen fluoride and that the fluorinated graphite thus produced will be novel.